21742422 has 64 divisors (see below), whose sum is σ = 52254720. Its totient is φ = 5958144.

The previous prime is 21742411. The next prime is 21742447. The reversal of 21742422 is 22424712.

It is a junction number, because it is equal to n+sod(n) for n = 21742392 and 21742401.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24763 + ... + 25625.

It is an arithmetic number, because the mean of its divisors is an integer number (816480).

Almost surely, 2^21742422 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21742422, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26127360).

21742422 is an abundant number, since it is smaller than the sum of its proper divisors (30512298).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21742422 is a wasteful number, since it uses less digits than its factorization.

21742422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917.

The product of its digits is 1792, while the sum is 24.

The square root of 21742422 is about 4662.8770088863. The cubic root of 21742422 is about 279.1060862483.

The spelling of 21742422 in words is "twenty-one million, seven hundred forty-two thousand, four hundred twenty-two".